The Frame Information Structure
The frame information structure defines a frame for a sequence grabber component and sequence grabber channel components. The
SeqGrabFrameInfo
data type defines the format of a frame information structure.
struct SeqGrabFrameInfo {
long frameOffset; /* offset to the sample */
long frameTime; /* time that frame was captured */
long frameSize; /* number of bytes in sample */
SGChannel frameChannel; /* current connection to channel */
long frameRefCon; /* reference constant for channel */
};
-
frameOffset
-
Specifies the offset to the sample.
-
frameTime
-
Specifies the time at which a sequence grabber channel component captured the frame. This time value is relative to the data sequence. That is, this time is not represented in the context of any fixed time scale. Rather, the channel component must choose and use a time scale consistently for all sample references.
-
frameSize
-
Specifies the number of bytes in the sample described by the sample reference.
-
frameChannel
-
Identifies the current connection to the channel component.
-
frameRefCon
-
Contains a reference constant for use by the channel component. A channel component can use this value in any way that is appropriate. For example, video channel components may use this value to store a reference to frame differencing information for a temporally compressed image sequence.
© 1997 Apple Computer, Inc.Previous | Chapter Top | Chapter Contents | Next
